TOPIC E - Biological explanations for criminality

Question 1

XYY

Answer 1

• A rare genetic disorder linked to aggression and slow learning ability
• The condition is not inherited so it does not run in families, even though it may be a genetic reason for criminality
• Theilgaard found that XYY males are more masculine and aggressive

Question 2

Family studies

Answer 2

• Involves comparing family trees of criminals and non-criminals
• If many of the criminal’s relatives are also criminals, there may be a biological basis for criminality.
• Some family studies show that a child is more likely to develop into a criminal if their parents or grandparents are criminals

Question 3

Adoption studies

Answer 3

• Look at relatives, siblings, and twins that are adopted at a young age
• Means they share genes but are not brought up in the same environment as their biological parents.
• By taking the environment out of the factor, we can be certain that genetics cause criminality

Question 4

Mendick (1984) - Supports adoption studies

Answer 4

• Looked at how many of the adopted children had criminal records compared to their biological and adoptive parents.
• Found that those adopted with criminal records for property theft also had biological fathers with criminal convictions even though were not raised by them.
• This was true to siblings separated and placed in different adoptive homes

Question 5

Monozygotic twins

Answer 5

Identical twins

Question 6

Dizygotic twins

Answer 6

Non-Identical twins

Question 7

Christiansen (1977) - Twin studies

• About the study
• Evidence

Answer 7

• Studied pairs of twins
• Found that if an identical twin was a criminal, the other would also be a criminal
• Only true 22% of non-identical twins perhaps because they share only half of their genes in common.
• Found the criminal link was for theft but not violent crimes
• Could be evidence of genetic basis to property crime as more than half of the identical twins studied share a criminal tendency.

Question 8

Argument for family and twin studies

Answer 8

• Genetics are not linked at all
• Since family members are raised and treated similarly, it could be that their criminal behavior is due to upbringing or observational learning.

Question 9

How to find if you have chromosome abnormalities

Answer 9

• Take blood samples from criminals to see if they have chromosome abnormalities that may have caused their criminal behavior

Question 10

Issues with the chromosome abnormality 1)

Answer 10

Chromosome abnormalities have been linked to violent crimes and murders have been found to have an XYY gene. However, this is true to only a handful of murders and definitely not true of all violent criminals

Question 11

Issues with the chromosome abnormality 2)

Answer 11

XYY is a very rare disorder that we cannot find a large enough sample of people to be certain of the link to violent crime. As XYY is linked to slow learning, having criminal tendency may be a result of not succeeding in school rather than a direct biological link to the disorder.